Aluminum salt-containing waste acid liquid recovery system

Abstract

The utility model discloses an aluminum salt-containing waste acid solution recovery system which comprises a first recovery subsystem, a second recovery subsystem and a third recovery subsystem, the first recovery subsystem is used for receiving an aluminum salt-containing waste acid solution and is suitable for separating the aluminum salt-containing waste acid solution to form a first filtrate and a second filtrate, and the second filtrate can circulate in the first recovery subsystem; the second recovery subsystem is connected with the first recovery subsystem, and the second recovery subsystem can receive the first filtered solution in the first recovery subsystem and is used for separating the first filtered solution to form a third filtered solution and a fourth filtered solution; the third recovery subsystem is connected with the second recovery subsystem, the third recovery subsystem can receive the fourth filtrate and is used for separating the fourth filtrate to form a fifth filtrate and a sixth filtrate, the sixth filtrate can circulate in the third recovery subsystem, and the third recovery subsystem can be used for preparing an aluminum salt solution. Therefore, the acid liquor can be recycled, the aluminum salt solution with the use value can be prepared, the aluminum salt-containing waste acid liquor is fully recycled, and zero emission is achieved.

Description

Technical Field

[0001] This application relates to the field of pickling waste liquid recovery technology, and in particular to a system for recovering aluminum salt-containing waste acid liquid. Background Technology

[0002] Aluminum and aluminum alloys are increasingly used in many fields such as the 3C (Computer, Communication, Consumer Electronics) industry, building materials, transportation, and electronics and power due to their advantages of abundant reserves, light weight, good thermal conductivity, good ductility and corrosion resistance.

[0003] Currently, in order to improve the corrosion resistance of aluminum alloys, the industry widely adopts anodizing to improve the performance of aluminum materials, thereby increasing the surface hardness and corrosion resistance.

[0004] In related technologies, in order to avoid the accumulation of aluminum ions in the pickling tank due to continuous production, which would affect the pickling effect, a common method is to add acid (such as sulfuric acid solution) to the pickling tank to dilute the aluminum ion concentration. However, adding acid will cause the acid to overflow and be discharged, and the recycling and treatment of waste acid is not ideal. Utility Model Content

[0005] This application aims to at least address one of the technical problems existing in the prior art. Therefore, one objective of this application is to provide an aluminum-containing waste acid recovery system capable of achieving full recovery and utilization of the aluminum-containing waste acid.

[0006] An aluminum-containing waste acid recovery system according to an embodiment of this application includes: a first recovery subsystem, which receives aluminum-containing waste acid and is adapted to separate the aluminum-containing waste acid into a first filtrate and a second filtrate, wherein the second filtrate can be circulated within the first recovery subsystem; a second recovery subsystem, which is connected to the first recovery subsystem and receives the first filtrate from the first recovery subsystem, and is used to separate the first filtrate into a third filtrate and a fourth filtrate; and a third recovery subsystem, which is connected to the second recovery subsystem and receives the fourth filtrate, and is used to separate the fourth filtrate into a fifth filtrate and a sixth filtrate, wherein the sixth filtrate can be circulated within the third recovery subsystem, and the third recovery subsystem can prepare an aluminum salt solution.

[0007] According to some embodiments of this application, the first recycling subsystem includes: a first storage tank for receiving the aluminum-containing waste acid liquid; a first separation device for separating the aluminum-containing waste acid liquid into a first filtrate and a second filtrate; and a first pump body connected between the first storage tank and the first separation device for pumping the solution in the first storage tank to the first separation device.

[0008] According to some embodiments of this application, the first separation device has a first separation liquid outlet and a second separation liquid outlet. The first separation liquid outlet is used to discharge the first filtrate, and the second separation liquid outlet is connected to the first storage tank and is used to discharge the second filtrate to the first storage tank.

[0009] According to some embodiments of this application, the second recovery subsystem includes: a second storage tank connected to the first storage tank and used to receive the first filtered solution; a second separation device connected downstream of the second storage tank; and a second pump body connected between the second storage tanks and used to pump the first filtered solution to the second separation device.

[0010] According to some embodiments of this application, the second separation device is provided with a pure water inlet for injecting pure water into the second separation device, and the second separation device is adapted to separate the mixed pure water from the first filtrate to form the third filtrate and the fourth filtrate; and / or, the second separation device is constructed as a diffusion dialysis membrane device.

[0011] According to some embodiments of this application, the second separation device has a third separation liquid outlet and a fourth separation liquid outlet, wherein the third separation liquid outlet is used to discharge the third filtrate, and the fourth separation liquid outlet is connected to the third recovery subsystem and is used to discharge the fourth filtrate to the third recovery subsystem.

[0012] According to some embodiments of this application, the aluminum-containing waste acid recovery system further includes: a first monitoring device, which is used to monitor the aluminum ion concentration in the first storage tank.

[0013] According to some embodiments of this application, the third recovery subsystem includes: a third storage tank connected to the second separation device and used to receive the fourth filtrate; a third separation device used to separate the fourth filtrate into the fifth filtrate and the sixth filtrate; and a third pump body connected between the third storage tank and the third separation device and used to pump the solution in the third storage tank to the third separation device.

[0014] According to some embodiments of this application, the third separation device has a fifth separation liquid outlet and a sixth separation liquid outlet. The fifth separation liquid outlet is used to discharge the fifth filtrate, and the sixth separation liquid outlet is connected to the third storage tank and is used to discharge the sixth filtrate to the third storage tank.

[0015] According to some embodiments of this application, the third recovery subsystem further includes a second monitoring device for monitoring the aluminum ion concentration in the third storage tank.

[0016] In summary, the aluminum-containing waste acid recovery system according to the embodiments of this application has at least the following advantages compared to the prior art:

[0017] The aluminum-containing waste acid recovery system of this application can recover the acid from aluminum-containing waste acid, enabling its reuse. It can also prepare a usable aluminum salt solution (e.g., aluminum sulfate solution) for use as a water treatment agent. The filtrate can be directly reused in the production line without generating other untreatable waste liquid, resulting in high process reliability. The aluminum-containing waste acid recovery system of this application has a simple process flow and does not require the introduction of chemical reactions or other materials, improving process reliability. It can effectively reduce the treatment cost of aluminum-containing waste acid and achieve full recovery and reuse, resulting in zero emissions.

[0018] The aluminum-containing waste acid recovery system in this embodiment involves a process of concentrating, separating, and further concentrating the aluminum salts in the waste acid solution to obtain an aluminum sulfate solution with the required aluminum salt and acid concentrations. This aluminum sulfate solution can be directly used as a water treatment agent. Furthermore, it improves the yield of the aluminum salt solution.

[0019] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0020] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0021] Figure 1 This is a schematic diagram of the structure of an aluminum-containing waste acid recovery system according to an embodiment of this application.

[0022] Figure label:

[0023] 100 aluminum salt waste acid recovery system;

[0024] First recovery subsystem 1; First storage tank 11; First inlet 111; First separation device 12; First separated liquid outlet 121; Second separated liquid outlet 122; First pump body 13;

[0025] Second recovery subsystem 2; Second storage tank 21; Second separation device 22; Third separation liquid outlet 221; Fourth separation liquid outlet 222; Third pump body 23;

[0026] Third recovery subsystem 3; Third storage tank 31; Aluminum salt solution outlet 311; Third separation device 32; Fifth separation liquid outlet 321; Sixth separation liquid outlet 322; Third pump body 33;

[0027] First monitoring device 41; second monitoring device 42. Detailed Implementation

[0028] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0029] The following is for reference. Figure 1 The present application describes an aluminum-containing waste acid recovery system 100. The aluminum-containing waste acid recovery system is used to recover and treat aluminum-containing waste acid to separate and prepare acid and aluminum salt solution, thereby recycling the aluminum-containing waste acid.

[0030] Reference Figure 1 The aluminum salt waste acid recovery system 100 includes a first recovery subsystem 1, a second recovery subsystem 2 and a third recovery subsystem 3.

[0031] The first recovery subsystem 1 is used to receive aluminum salt waste acid liquid, and the first recovery subsystem 1 can separate the aluminum salt waste acid liquid into a first filtrate and a second filtrate. The second filtrate can be circulated in the first recovery subsystem 1. That is to say, the first filtrate formed after separation is discharged from the first recovery subsystem 1, and the second filtrate can participate in the next separation cycle in the first circulation subsystem, and be separated again by the first recovery subsystem 1 to form the first filtrate and the second filtrate.

[0032] Reference Figure 1 The second recovery subsystem 2 is connected to the first recovery subsystem 1, and the second recovery subsystem 2 can receive the first filtrate from the first recovery subsystem 1, and the second recovery subsystem 2 is used to separate the first filtrate to form the third filtrate and the fourth filtrate.

[0033] It should be noted that the "first filtrate solution" is the solution produced after multiple cycles of the first recovery subsystem 1. In other words, the first filtrate solution can be formed from the second filtrate after multiple cycles.

[0034] Understandably, the second recovery subsystem 2 is used to further separate the product (i.e. the first filtrate) after the aluminum salt waste acid solution is separated by the first recovery subsystem 1 to form the third filtrate and the fourth filtrate. The third filtrate no longer participates in the separation or recycling, and the fourth filtrate can be further transported to the third recovery subsystem 3.

[0035] Reference Figure 1 The third recovery subsystem 3 is connected to the second recovery subsystem 2. The third recovery subsystem 3 can receive the fourth filtrate, and the third recovery subsystem 3 is used to separate the fourth filtrate into the fifth filtrate and the sixth filtrate. The sixth filtrate can be circulated in the third recovery subsystem 3, and an aluminum salt solution can be prepared through the third recovery subsystem 3.

[0036] Understandably, the third recovery subsystem 3 can receive the fourth filtrate formed by the separation in the second recovery subsystem 2, and the third recovery subsystem 3 can further separate the fourth filtrate to form the fifth and sixth filtrates. The fifth filtrate does not participate in the separation or recycling, while the sixth filtrate can be further recycled and separated in the third recovery subsystem 3 to prepare an aluminum salt solution through the third recovery subsystem 3.

[0037] Therefore, the first recovery subsystem 1 can filter out the first filtrate, the second recovery subsystem 2 can filter out the third filtrate, and the third recovery subsystem 3 can filter out the fifth filtrate to form an aluminum salt solution. In other words, the aluminum salt waste acid recovery system 100 of this application can achieve multi-stage separation of the aluminum salt waste acid to prepare various solutions, such as: a concentrated acid solution with high acidity (e.g., the first filtrate), an acid solution with low acidity (e.g., the third and fifth filtrates), and an aluminum salt solution, thereby fully recovering and utilizing the aluminum salt waste acid.

[0038] The terms "higher acidity" and "lower acidity" mentioned above refer to the comparison between two solutions and do not represent the specific acidity of the solutions. Furthermore, the acid solutions prepared by the aluminum salt waste acid recovery system 100 (such as the first, third, and fifth filtrates mentioned above) can be reused in the pickling process, and the resulting aluminum salt solution is the finished product, achieving a balance of aluminum salts within the production line system.

[0039] It should be noted that aluminum and aluminum alloys are increasingly widely used in many fields such as the 3C (Computer, Communication, Consumer Electronics) industry, building materials, transportation, and electronics and power due to their advantages of abundant reserves, light weight, good thermal conductivity, good ductility, and corrosion resistance. Currently, to improve the corrosion resistance of aluminum alloys, the industry widely adopts anodizing to enhance the performance of aluminum materials, thereby improving the surface hardness and corrosion resistance.

[0040] In related technologies, in order to avoid the accumulation of aluminum ions in the pickling tank due to continuous production, which would affect the pickling effect, a common method is to add acid (such as sulfuric acid solution) to the pickling tank to dilute the aluminum ion concentration. However, adding acid will cause the acid to overflow and be discharged, and the recycling and treatment of waste acid is not ideal.

[0041] Specifically, methods for recovering aluminum ions from pickling tanks include ion exchange, dialysis, and nanofiltration. Among these, the ion exchange resin method consumes a large amount of water and still discharges waste acid; the dialysis method is inefficient and time-consuming; the nanofiltration method can recover 60%-90% of the waste acid, but it also produces untreated waste acid, and the discharge of this waste acid can also cause metal pollution hazards.

[0042] In the aluminum salt waste acid recovery system 100 of this application embodiment, the aluminum salt waste acid can be separated and recovered multiple times to separate the acid solution (i.e. the first filtrate, the third filtrate and the fifth filtrate mentioned above) and the aluminum salt solution. The acid solution can be reused in the pickling process in the production line to realize the reuse of the acid solution. The aluminum salt solution is extracted from the aluminum salt waste acid to realize the balance of aluminum salt in the original production line system. Thus, the aluminum salt waste acid can be fully recovered and reused, and the waste acid can be discharged in zero.

[0043] like Figure 1As shown, in some embodiments of this application, the first recycling subsystem 1 includes: a first storage tank 11, a first separation device 12, and a first pump body 13. The first storage tank 11 is used to receive aluminum salt waste acid liquid, the first separation device 12 is used to separate the aluminum salt waste acid liquid to form a first filtrate and a second filtrate, and the first pump body 13 is connected between the first storage tank 11 and the first separation device 12, and the first pump body 13 is used to pump the solution in the first storage tank 11 to the first separation device 12.

[0044] The "solution" pumped by the first pump body 13 to the first separation device 12 can be aluminum salt waste acid liquid, or it can be a mixture of aluminum salt waste acid liquid and second filtrate.

[0045] Reference Figure 1 The first storage tank 11 has a first inlet 111 for receiving aluminum-containing waste acid. The first storage tank 11 serves as a storage container for the aluminum-containing waste acid. Under the action of the first pump body 13, the solution in the first storage tank 11 can be pumped to the first separation device 12. The first separation device 12 can separate the solution into a first filtrate and a second filtrate. Thus, primary separation of the aluminum-containing waste acid is achieved through the first separation device 12.

[0046] The second filtrate after separation can flow back to the first storage tank 11 and be pumped again by the first pump body 13 to the first separation device 12 for separation and filtration.

[0047] It should be noted that the first separation device 12 can intercept aluminum ions in the second filtrate. The first filtrate is an acid solution. That is to say, by concentrating the aluminum salt waste acid solution through the first separation device 12, the concentration of acid radicals (such as sulfate concentration) in the separated first filtrate increases, so that the first filtrate can meet the requirements for reuse in the production line. The first filtrate can be directly returned to the production line for reuse, while the second filtrate can be returned to the first storage tank 11 for circulation and concentration.

[0048] In some embodiments of this application, the first separation device 12 is configured as a nanofiltration membrane separation device, which can effectively increase the concentration of acid radicals in the solution. Taking aluminum-containing waste acid solution as an example, the nanofiltration membrane separation device can concentrate the sulfate, thereby increasing the sulfate concentration in the first filtrate, decreasing the sulfate concentration in the second filtrate, and increasing the aluminum ion concentration. This allows the concentration and filtration separation process of the first recovery subsystem 1 to be stopped when the aluminum ion content in the solution in the first storage tank 11 reaches a preset value (e.g., 30 g / L), and the first filtered solution in the first storage tank 11 to be transported to the second recovery subsystem 2.

[0049] In a further embodiment of this application, the nanofiltration membrane separation device may be configured as one of a spiral wound nanofiltration membrane separation device, a hollow fiber nanofiltration membrane separation device, or a ceramic nanofiltration membrane separation device.

[0050] It should be noted that the nanofiltration membrane separation device in this application is used to recover aluminum-containing waste acid liquid. The filter membrane module in the nanofiltration membrane separation device is an acid-resistant nanofiltration membrane module, and the molecular weight cutoff of organic matter in the acid-resistant nanofiltration membrane module is preferably in the range of 150-500, and the rejection rate of solution salts is preferably in the range of 80%-98%. The nanofiltration membrane separation device has virtually no effect on the concentration of acid liquid (e.g., sulfuric acid concentration), thus ensuring that the first filtrate filtered by the nanofiltration membrane separation device meets the reuse requirements of the production line.

[0051] like Figure 1 As shown, in some embodiments of this application, the first separation device 12 has a first separation liquid outlet 121 and a second separation liquid outlet 122. The first separation liquid outlet 121 is used to discharge the first filtrate, and the second separation liquid outlet 122 is connected to the first storage tank 11. The second filtrate flowing out through the second separation liquid outlet 122 can be returned to the first storage tank 11 for cyclic concentration, separation and filtration.

[0052] The acidity of the first filtrate meets the reuse requirements of the production line, meaning that the first separated liquid outlet 121 can be directly connected to the production line. Of course, the first separated liquid outlet 121 can also be connected to an acid storage device; no specific limitation is made here.

[0053] like Figure 1 As shown, in some embodiments of this application, the second recovery subsystem 2 includes: a second storage tank 21, a second separation device 22, and a second pump body.

[0054] Reference Figure 1 The second storage tank 21 is connected to the first storage tank 11, and the second storage tank 21 is used to receive the first filtered solution in the first storage tank 11. The first filtered solution is a solution that has undergone multiple cycles of filtration and separation, and the aluminum ion concentration in the first filtered solution reaches a preset value.

[0055] Furthermore, the second separation device 22 is connected downstream of the second storage tank 21, and the second pump body is connected between the second storage tanks 21. The second pump body is used to pump the first filtrate solution to the second separation device 22 so that the first filtrate solution is further separated and filtered by the second separation device 22 to form the third filtrate and the fourth filtrate.

[0056] like Figure 1As shown, in a further embodiment of this application, the second separation device 22 is provided with a pure water inlet, which is used to inject pure water into the second separation device 22, and the second separation device 22 is adapted to separate the mixed pure water from the first filtrate solution to form a third filtrate and a fourth filtrate.

[0057] In the process of solution separation through the second recovery subsystem 2, the first filtered solution is pumped to the second separation device 22 by the second pump body, while pure water is injected into the second separation device 22, so that the solution is further separated and filtered by the second separation device 22.

[0058] It is understandable that by injecting pure water into the second separation device 22, the concentration of aluminum ions and acid radicals in the solution formed after the pure water in the second separation device 22 is mixed with the first filtrate is reduced, so as to ensure the filtration and separation effect of the second separation device 22 on the solution, thereby facilitating the further separation of acid by the second separation device 22, that is, the separation by the second separation device 22 to form the third filtrate.

[0059] In some embodiments of this application, the second separation device 22 is configured as a diffusion dialysis membrane device, which can further separate the acid solution.

[0060] Understandably, in the separation and filtration process of a diffusion dialysis membrane device, taking aluminum sulfate as an example, sulfuric acid has a higher permeability, thus allowing more acid solution (i.e., sulfuric acid solution) to be separated.

[0061] During the recovery process of the second recovery subsystem 2, the flow rate of the solution pumped from the second storage tank 21 to the second separation device 22 via the second pump body is similar to or the same as the flow rate of pure water injected into the second separation device 22 via the pure water inlet. For example, the flow rate of the solution pumped from the second pump body to the second separation device 22 is 0.5t / h, and the flow rate of pure water injected into the second separation device 22 via the pure water inlet is also controlled at 0.5t / h.

[0062] It should be noted that the third filtrate formed by the second separation device 22 is an acid solution, and the acidity of the third filtrate is lower than that of the first filtrate. When the third filtrate needs to be reused in the production line, acid solution can be added to the third filtrate according to the acidity requirements of the process in the production line. The specific acidity can be controlled by the acid addition device in the production line.

[0063] In some preferred examples, when the aluminum salt is aluminum sulfate, the diffusion dialysis device has a sulfuric acid recovery rate of 60%-65% (preferably 63%) and an aluminum ion rejection rate of 85%-95% (preferably 90%).

[0064] In one specific embodiment of this application, an anion exchange membrane can be used in the diffusion dialysis device, with the anion exchange membrane having a sulfuric acid recovery rate of 50%-70% and an aluminum removal rate of 80%-90%.

[0065] like Figure 1 As shown, in some embodiments of this application, the second separation device 22 has a third separation liquid outlet 221 and a fourth separation liquid outlet 222. The third separation liquid outlet 221 is used to discharge the third filtrate, and the fourth separation liquid outlet 222 is connected to the third recovery subsystem 3 and can discharge the fourth filtrate to the third recovery subsystem 3 through the fourth separation liquid outlet 222.

[0066] The third separation liquid outlet 221 can be connected to the production line to return the third filtrate formed by separation to the production line side, realizing the reuse of the third filtrate. It is understood that even if a small amount of aluminum ions are present in the third filtrate, it will not affect the overall acidity of the third filtrate, and the third filtrate can still be reused in the production line. Furthermore, when the third filtrate is reused in the production line, the acidity of the third filtrate reused in the production line can be adjusted and controlled by an acid addition device.

[0067] like Figure 1 As shown, in some embodiments of this application, the aluminum salt waste acid recovery system 100 further includes: a first monitoring device 41 and a second monitoring device 42.

[0068] The first monitoring device 41 is used to monitor the aluminum ion concentration in the first storage tank 11, so as to control the operation status of the first recovery subsystem 1 according to the aluminum ion concentration in the first storage tank 11.

[0069] Understandably, the first recovery subsystem 1 can separate and form a first filtrate and a second filtrate, and the second filtrate is circulated and concentrated in the first recovery subsystem 1. The aluminum ion concentration in the solution in the first storage tank 11 gradually increases with repeated filtration cycles in the first recovery subsystem 1, and when the first monitoring device 41 detects that the aluminum ion concentration in the first storage tank 11 has reached a preset value, the filtration cycle of the first recovery subsystem 1 can be stopped, and the solution in the first storage tank 11 can be transferred to the second storage tank 21 (i.e., the second recovery subsystem 2 side) for further separation and filtration by the second recovery subsystem 2.

[0070] Furthermore, the control device (not shown) in the aluminum salt waste acid recovery system 100 can be electrically connected to the first monitoring device 41, and the control device can also be used to control the first pump body 13 and the second pump body, so that the control device can control the operating status (i.e., on or off) of the first pump body 13 and the second pump body based on the monitoring signal of the first monitoring device 41. For example, during the operation of the first recovery subsystem 1, the aluminum ion concentration in the first storage tank 11 is monitored by the first monitoring device 41. When the aluminum ion concentration in the first storage tank 11 reaches a preset value, the first pump body 13 can be controlled to close by the control device, and the solution in the first storage tank 11 can be discharged to the second recovery subsystem 2. After the solution is discharged into the second recovery subsystem 2, the second pump body can be controlled to open by the control device so that the solution can be further separated and filtered by the second recovery subsystem 2.

[0071] like Figure 1 As shown, in some embodiments of this application, the third recovery subsystem 3 includes: a third storage tank 31, a third separation device 32, and a third pump body 33.

[0072] The third storage tank 31 is connected to the second separation device 22 and is used to receive the fourth filtrate. In other words, the fourth filtrate outlet 222 of the second separation device 22 is connected to the third storage tank 31, so that the fourth filtrate formed by the second separation device 22 can directly enter and be stored in the third storage tank 31.

[0073] Furthermore, the third separation device 32 is used to separate the fourth filtrate into a fifth filtrate and a sixth filtrate. The third pump body 33 is connected between the third storage tank 31 and the third separation device 32, and is used to pump the solution in the third storage tank 31 to the third separation device 32. It should be noted that the "solution in the third storage tank 31" can be the fourth filtrate, or it can be a mixed solution of the fourth filtrate and the sixth filtrate returned to the third storage tank 31.

[0074] In the third recovery subsystem 3, the solution pumped to the third separation device 32 by the third pump 33 can be separated and filtered to form a fifth filtrate and a sixth filtrate. The fifth filtrate can be discharged from the third separation device 32, and the sixth filtrate can be returned to the third storage tank 31 for further filtration. It is understood that as the solution circulates and filters in the third subsystem, the aluminum ion concentration in the solution in the third storage tank 31 gradually increases, and when the aluminum ion concentration in the third storage tank 31 reaches a preset value, the solution in the third storage tank 31 becomes the finished aluminum salt solution.

[0075] like Figure 1As shown, the third storage tank 31 is provided with an aluminum salt solution outlet 311. When the finished product forming an aluminum salt solution is prepared in the third storage tank 31, the aluminum salt solution can be discharged through the aluminum salt solution outlet 311 to facilitate the collection of the finished aluminum salt solution.

[0076] In some embodiments of this application, the third recovery subsystem 3 further includes a second monitoring device 42, which is used to monitor the aluminum ion concentration in the third storage tank 31. When the aluminum ion concentration in the third storage tank 31 reaches a preset value, it indicates that the solution in the third storage tank 31 is the finished product of the prepared aluminum salt solution, and the finished product can be directly collected through the aluminum salt solution outlet 311.

[0077] Understandably, the control device in the aluminum salt waste acid recovery system 100 can be electrically connected to the second monitoring device 42, and the control device can be used to control the operating status (i.e., open or closed) of the third pump body 33. When the second monitoring device 42 detects that the aluminum ion concentration in the solution in the third storage tank 31 reaches a preset value (e.g., 40 g / L), the control device can control the third pump body 33 to close and collect the finished aluminum salt solution from the aluminum salt solution outlet 311.

[0078] In some embodiments of this application, the third separation device 32 has a fifth separation liquid outlet 321 and a sixth separation liquid outlet 322. The fifth separation liquid outlet 321 is used to discharge the fifth filtrate, and the sixth separation liquid outlet 322 is connected to the third storage tank 31. The sixth separation liquid outlet 322 can discharge the sixth filtrate to the third storage tank 31 to realize the circulation and concentration of the solution in the third recovery subsystem 3.

[0079] In some embodiments of this application, the third separation device 32 is configured as a nanofiltration membrane separation device, in which a ceramic acid-resistant nanofiltration membrane can be selected, thereby allowing the solution to be separated and filtered through the nanofiltration membrane separation device.

[0080] The fifth filtrate formed by the third separation device 32 has a low acidity. When the fifth filtrate needs to be returned to the production line, acid can be added to the fifth filtrate through the acid addition device in the production line to adjust the acidity of the solution.

[0081] In other words, some of the equipment in the aluminum salt waste acid recovery system 100 of this application can be connected to a production line with an aluminum pickling process to realize the recovery and reuse of acid (i.e., the first filtrate, the third filtrate and the fifth filtrate mentioned above).

[0082] It should be noted that the aluminum salt in the aluminum-containing waste acid recovery system 100 can be sulfate, nitrate, etc. The working process of the aluminum-containing waste acid system in this application embodiment is described with aluminum salt as sulfate:

[0083] The waste liquid from the anodizing tank (i.e., aluminum-containing waste acid liquid) collected from the production line is injected into the first storage tank 11. The aluminum ion concentration in the solution in the first storage tank 11 is monitored by the first monitoring device 41, and the sulfuric acid concentration can also be monitored, for example: the aluminum ion concentration is 9 g / L and the sulfuric acid concentration is 190 g / L.

[0084] The solution is further pumped to the first separation device 12 (e.g., a nanofiltration membrane separation device using a spiral-wound acid-resistant nanofiltration membrane) via the first pump body 13. The first separation device 12 separates the solution into a first filtrate and a second filtrate. The first filtrate is sulfuric acid, and its concentration can be maintained at approximately 190 g / L, meeting the requirements for reuse in the production line. The second filtrate is then returned to the first storage tank 11 for further concentration. The first filtrate also contains a certain amount of aluminum ions, but the concentration is low (e.g., around 1 g / L), which does not affect the reuse effect of the first filtrate in the production line.

[0085] During the process of solution circulation separation and concentration through the first recovery subsystem 1, the aluminum ion concentration in the solution in the first storage tank 11 can be monitored in real time by the first monitoring device 41, and when the aluminum ion concentration in the solution reaches a preset value (e.g., 30 g / L), the first pump body 13 is shut off and the solution in the first storage tank 11 is transferred to the second storage tank 21.

[0086] In the second recovery subsystem 2, the second separation device 22 is constructed as a diffusion dialysis membrane device using anion exchange membrane. The flow rate of the solution pumped in by the second pump body is 0.5 t / h. Simultaneously, pure water is injected into the second separation device 22 through a pure water inlet at a flow rate of 0.5 t / h. The second separation device 22 separates the solution into a third filtrate and a fourth filtrate. The sulfuric acid concentration in the third filtrate is 120 g / L, and the aluminum ion concentration is 3 g / L, which meets the requirements for reuse in the production line. Furthermore, the acidity of the third filtrate can be increased by adding acid during reuse. The fourth filtrate can flow directly into the third recovery subsystem 3. The diffusion dialysis membrane achieves a sulfuric acid recovery rate of approximately 63% and an aluminum ion retention rate of approximately 90%.

[0087] In the third recovery subsystem 3, the third separation device 32 can be constructed as a nanofiltration membrane separation device using a ceramic acid-resistant nanofiltration membrane. The fourth filtrate entering the third recovery subsystem 3 is aluminum-rich brine. After being separated by the third separation device 32, it can form a fifth filtrate and a sixth filtrate. The aluminum ion content in the fifth filtrate is about 3 g / L, and the sulfuric acid content is about 70 g / L. It can be reused in the production line. During the reuse process, the acidity can be controlled by adding acid through an acid adding device. The sixth filtrate can flow back to the third storage tank 31 and be circulated and concentrated.

[0088] During the process of solution circulation separation and concentration through the third recovery subsystem 3, the aluminum ion concentration in the solution in the third storage tank 31 can be monitored in real time by the second monitoring device 42, and the third pump 33 is shut off when the aluminum ion concentration in the solution reaches a preset value (e.g., 40 g / L), and the finished aluminum sulfate solution in the third storage tank 31 is collected through the aluminum salt solution outlet 311.

[0089] The aluminum-containing waste acid recovery system 100 according to the embodiments of this application has at least the following advantages compared with the prior art:

[0090] The aluminum-containing waste acid recovery system 100 of this application can recover the acid from aluminum-containing waste acid, enabling the reuse of the acid. It can also prepare a usable aluminum salt solution (such as aluminum sulfate solution) for use as a water treatment agent. The filtrate can be directly reused in the production line without generating other untreatable waste liquid, resulting in high process reliability. The aluminum-containing waste acid recovery system 100 of this application has a simple process flow and does not require the introduction of chemical reactions or other materials, improving the reliability of the process flow. It can effectively reduce the treatment cost of aluminum-containing waste acid and achieve full recovery and reuse of the aluminum-containing waste acid, realizing zero discharge.

[0091] The aluminum-containing waste acid recovery system 100 in this embodiment of the application uses a process of concentrating, separating, and further concentrating aluminum salts in the waste acid solution to obtain an aluminum sulfate solution with the required aluminum salt and acid concentrations. This aluminum sulfate solution can be directly used as a water treatment agent. Simultaneously, it can also improve the yield of the aluminum salt solution.

[0092] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0093] In the description of this application, "first feature" and "second feature" may include one or more of the features.

[0094] In the description of this application, "multiple" means two or more.

[0095] In the description of this application, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or the first and second features being in contact through another feature between them.

[0096] In the description of this application, the terms "above," "over," and "on top" for the first feature and the second feature include the first feature being directly above or diagonally above the second feature, or simply indicate that the first feature is at a higher horizontal level than the second feature.

[0097] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0098] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A system for recovering spent acid containing aluminum salt, characterized by, The application relates to a recovery system for recovering aluminum salt waste acid liquid, comprising: a first recovery subsystem (1) for receiving the aluminum salt waste acid liquid and separating the aluminum salt waste acid liquid into a first filtrate and a second filtrate, and the second filtrate can be recycled in the first recovery subsystem (1); a second recovery subsystem (2) connected with the first recovery subsystem (1), the second recovery subsystem (2) can receive the first filtrate in the first recovery subsystem (1) and separate the first filtrate into a third filtrate and a fourth filtrate; a third recovery subsystem (3) connected with the second recovery subsystem (2), the third recovery subsystem (3) can receive the fourth filtrate and separate the fourth filtrate into a fifth filtrate and a sixth filtrate, the sixth filtrate can be recycled in the third recovery subsystem (3), and the third recovery subsystem (3) can prepare an aluminum salt solution.

2. The system for recovering aluminum-containing salt spent acid according to claim 1, wherein The first recovery subsystem (1) comprises: a first storage tank (11) for receiving the aluminum salt waste acid liquid; a first separation device (12) for separating the aluminum salt waste acid liquid into the first filtrate and the second filtrate; a first pump body (13) connected between the first storage tank (11) and the first separation device (12) and used for pumping the solution in the first storage tank (11) to the first separation device (12).

3. The system for recovering aluminum-containing salt spent acid according to claim 2, wherein The first separation device (12) has a first separation liquid outlet (121) for discharging the first filtrate and a second separation liquid outlet (122) in communication with the first storage tank (11) and used for discharging the second filtrate to the first storage tank (11).

4. The system for recovering aluminum-containing salt spent acid according to claim 2, wherein The second recovery subsystem (2) comprises: a second storage tank (21) connected with the first storage tank (11) and used for receiving the first filtrate; a second separation device (22) connected downstream of the second storage tank (21); a second pump body connected between the second storage tank (21) and used for pumping the first filtrate to the second separation device (22).

5. The system for recovering aluminum-containing salt spent acid according to claim 4, wherein The second separation device (22) is provided with a pure water inlet used for injecting pure water into the second separation device (22), and the second separation device (22) is suitable for separating the mixed pure water and the first filtrate into the third filtrate and the fourth filtrate; and / or, the second separation device (22) is configured as a diffusion dialysis membrane device.

6. The system for recovering aluminum-containing salt spent acid according to claim 4, wherein The second separation device (22) has a third separated liquid outlet (221) and a fourth separated liquid outlet (222), the third separated liquid outlet (221) is used for discharging the third filtrate, and the fourth separated liquid outlet (222) is communicated with the third recovery subsystem (3) and is used for discharging the fourth filtrate to the third recovery subsystem (3).

7. The system for recovering aluminum-containing salt spent acid according to claim 4, wherein The waste acid liquid recovery system further comprises a first monitoring device (41) configured to monitor the concentration of aluminum ions in the first storage tank (11).

8. The system for recovering aluminum-containing salt spent acid according to claim 4, wherein The third recovery subsystem (3) comprises: a third storage tank (31) connected with the second separation device (22) and configured to receive the fourth filtrate; a third separation device (32) configured to separate the fourth filtrate into the fifth filtrate and the sixth filtrate; a third pump body (33) connected between the third storage tank (31) and the third separation device (32) and configured to pump the solution in the third storage tank (31) to the third separation device (32).

9. The system for recovering aluminum-containing salt spent acid according to claim 8, wherein, The third separation device (32) has a fifth separated liquid outlet (321) and a sixth separated liquid outlet (322), the fifth separated liquid outlet (321) is used for discharging the fifth filtrate, and the sixth separated liquid outlet (322) is communicated with the third storage tank (31) and is used for discharging the sixth filtrate to the third storage tank (31).

10. The system for recovering aluminum-containing salt spent acid according to claim 8, wherein The third recovery subsystem (3) further comprises a second monitoring device (42) configured to monitor the concentration of aluminum ions in the third storage tank (31). The waste acid liquid recovery system further comprises a first monitoring device (41) configured to monitor the concentration of aluminum ions in the first storage tank (11).

Images